Bug#27990: Wrong info in MYSQL_FIELD struct members when a tmp table was used.

The change_to_use_tmp_fields function leaves the orig_table member of an
expression's tmp table field filled for the new Item_field being created.
Later orig_table is used by the Field::make_field function to provide some
info about original table and field name to a user. This is ok for a field
but for an expression it should be empty.

The change_to_use_tmp_fields function now resets orig_table member of
an expression's tmp table field to prevent providing a wrong info to a user.
The Field::make_field function now resets the table_name and the org_col_name
variables when the orig_table is set to 0.


sql/field.cc:
  Bug#27990: Wrong info in MYSQL_FIELD struct members when a tmp table was used.
  The Field::make_field function now resets the table_name and the org_col_name
  variables when the orig_table is set to 0.
sql/sql_select.cc:
  Bug#27990: Wrong info in MYSQL_FIELD struct members when a tmp table was used.
  The change_to_use_tmp_fields function now resets orig_table member of
  an expression's tmp table field to prevent providing a wrong info to a user.
tests/mysql_client_test.c:
  The test case for the bug#21635 is altered to test behavior on both const and
  non-const tables.

1 files changed, 26 insertions, 19 deletions

diff --git a/tests/mysql_client_test.c b/tests/mysql_client_test.c
index d64ec08a71d..3e50e1ede84 100644
--- a/tests/mysql_client_test.c
+++ b/tests/mysql_client_test.c
@@ -15486,7 +15486,7 @@ static void test_bug21635()
   char *query_end;
   MYSQL_RES *result;
   MYSQL_FIELD *field;
-  unsigned int field_count, i;
+  unsigned int field_count, i, j;
   int rc;
 
   DBUG_ENTER("test_bug21635");
@@ -15502,28 +15502,35 @@ static void test_bug21635()
   myquery(rc);
   rc= mysql_query(mysql, "CREATE TABLE t1 (i INT)");
   myquery(rc);
-  rc= mysql_query(mysql, "INSERT INTO t1 VALUES (1)");
-  myquery(rc);
+  /*
+    We need this loop to ensure correct behavior with both constant and
+    non-constant tables.
+  */
+  for (j= 0; j < 2 ; j++)
+  {
+    rc= mysql_query(mysql, "INSERT INTO t1 VALUES (1)");
+    myquery(rc);
 
-  rc= mysql_real_query(mysql, query, query_end - query);
-  myquery(rc);
+    rc= mysql_real_query(mysql, query, query_end - query);
+    myquery(rc);
 
-  result= mysql_use_result(mysql);
-  DIE_UNLESS(result);
+    result= mysql_use_result(mysql);
+    DIE_UNLESS(result);
 
-  field_count= mysql_field_count(mysql);
-  for (i= 0; i < field_count; ++i)
-  {
-    field= mysql_fetch_field_direct(result, i);
-    printf("%s -> %s ... ", expr[i * 2], field->name);
-    fflush(stdout);
-    DIE_UNLESS(field->db[0] == 0 && field->org_table[0] == 0 &&
-               field->table[0] == 0 && field->org_name[0] == 0);
-    DIE_UNLESS(strcmp(field->name, expr[i * 2 + 1]) == 0);
-    puts("OK");
-  }
+    field_count= mysql_field_count(mysql);
+    for (i= 0; i < field_count; ++i)
+    {
+      field= mysql_fetch_field_direct(result, i);
+      printf("%s -> %s ... ", expr[i * 2], field->name);
+      fflush(stdout);
+      DIE_UNLESS(field->db[0] == 0 && field->org_table[0] == 0 &&
+                 field->table[0] == 0 && field->org_name[0] == 0);
+      DIE_UNLESS(strcmp(field->name, expr[i * 2 + 1]) == 0);
+      puts("OK");
+    }
 
-  mysql_free_result(result);
+    mysql_free_result(result);
+  }
   rc= mysql_query(mysql, "DROP TABLE t1");
   myquery(rc);